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  1. AP Environmental Science
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Glossary

C

Chain reaction

Criticality: 2

A self-sustaining series of nuclear fissions where neutrons released from one fission event cause further fission events in other atomic nuclei.

Example:

In a nuclear reactor, control rods are used to manage the chain reaction to prevent it from becoming uncontrolled and overheating.

Chernobyl

Criticality: 3

A catastrophic 1986 nuclear accident in Ukraine (then USSR) caused by a power surge that led to a reactor explosion, releasing massive amounts of radioactive material and causing widespread contamination.

Example:

The exclusion zone around Chernobyl remains largely uninhabitable decades after the devastating reactor explosion.

Control Rods

Criticality: 3

Components made of neutron-absorbing materials (like cadmium or boron) inserted into a nuclear reactor core to regulate the rate of fission and prevent a runaway chain reaction.

Example:

Operators can adjust the depth of the control rods within the reactor to slow down or speed up the nuclear fission process.

F

Fission

Criticality: 3

A nuclear reaction in which a heavy atomic nucleus splits into two or more smaller nuclei, releasing a large amount of energy.

Example:

In a nuclear power plant, the controlled fission of uranium atoms generates the heat needed to produce steam.

Fukushima Daiichi

Criticality: 3

A 2011 nuclear accident in Japan, triggered by a massive earthquake and tsunami, which caused a loss of power and cooling, leading to meltdowns and hydrogen explosions in multiple reactors.

Example:

The Fukushima Daiichi disaster demonstrated the vulnerability of nuclear power plants to natural disasters, even with advanced safety features.

Fusion

Criticality: 2

A nuclear reaction in which two or more light atomic nuclei combine to form a heavier nucleus, releasing a tremendous amount of energy.

Example:

Scientists are working to replicate the fusion process that powers the sun, hoping to create a clean and virtually limitless energy source on Earth.

N

Non-Renewable (Nuclear Fuel)

Criticality: 2

A resource that exists in finite quantities and cannot be replenished on a human timescale, such as uranium used for nuclear energy.

Example:

Although nuclear power doesn't emit greenhouse gases, its reliance on non-renewable uranium means it's not a truly sustainable long-term energy solution.

Nuclear Accidents

Criticality: 3

Incidents at nuclear power plants that result in the release of radioactive materials or significant damage to the reactor core, posing risks to human health and the environment.

Example:

The history of nuclear accidents highlights the critical importance of stringent safety protocols and emergency preparedness in the nuclear industry.

Nuclear energy

Criticality: 3

Energy released from the nucleus of an atom, typically through nuclear fission or fusion, and harnessed to generate electricity.

Example:

Many countries are exploring nuclear energy as a way to reduce carbon emissions, despite concerns about waste disposal.

P

Plutonium

Criticality: 1

A radioactive metallic element, often produced as a byproduct in nuclear reactors, that can also be used as nuclear fuel or in weapons.

Example:

While uranium is the main fuel, some advanced reactors can use plutonium as a fuel source, which also helps reduce radioactive waste.

R

Radioactive waste

Criticality: 3

Hazardous byproduct materials from nuclear power generation or other nuclear processes that emit ionizing radiation and remain dangerous for thousands of years.

Example:

The safe, long-term disposal of radioactive waste is one of the most significant challenges facing the nuclear energy industry.

T

Thermal pollution

Criticality: 2

The degradation of water quality by any process that changes ambient water temperature, often caused by the discharge of heated water from industrial processes like nuclear power plants.

Example:

Nuclear power plants often release heated water into nearby rivers or lakes, causing thermal pollution that can harm aquatic ecosystems.

Three Mile Island

Criticality: 2

A 1979 nuclear accident in Pennsylvania, USA, involving a partial meltdown of the reactor core due to a cooling malfunction, leading to a minor release of radioactive gas.

Example:

The Three Mile Island incident led to significant changes in nuclear power plant regulations and safety procedures in the United States.

U

Uranium (U-235)

Criticality: 3

A naturally occurring radioactive element, specifically the U-235 isotope, which is the primary fuel source used in nuclear fission reactors.

Example:

The rare isotope Uranium-235 is enriched from mined uranium ore to be used as fuel rods in nuclear power plants.